Apparently so.

I just did my car for you.

It's an 03 S-type 3.0. I've never had any problems with the gas gauge, though I do tend to fill up once I pass the 1/4 mark.

Here were my readings:

Raw Fuel 1: 175
Raw Fuel 2: 28
Filter fuel 1: 204
Filter Fuel 2: 10

Fuel Percent = 100

This is with an indicated 3.5/8 of a tank approximately, and 140 miles range.

My guess is the tank doesn't empty evenly. It probably empties the side closer to the fuel lines first, then proceeds to the further side. Although the other day when i did it they were both in the low 200's. apparently the scale is 1-254. Now let's say the tank is 18.5 gallons. Let's also assume that the tank is evenly divided. If we subtract the 1.5 gallon reserve, there are 17 gallons of possible indicated fuel.

so if 17 gallons of fuel = indicated full, then you would have 254 (Fuel 1) + 254 (Fuel 2) = 508 total.

508 / 17 = 29.88 per gallon.

My car's current cumulative fuel number = 203

203 / 29.88 = 6.79 gallons of fuel aboard reported. 6.79 /17 = 39.9%

3.5/8 (approximate gas gauge indication) = 43.75% of fuel aboard.

Any my indicated range of 140 miles / 6.79 gallons of fuel = 20.61 estimate mpg on the rest of the gas, which is about right.

So that's how I believe the calculations go. The real low fuel filter 2 number makes me suspect and believe that there is uneven fuel flow from the two sides of the tank rather than an erratic sensor on one side.

NOW THE KEY, Is to go fill the car up, and see how much actual fuel it took on. Then immediately start the car in test mode and get the readings, both to see how accurate my math is, and secondly if the indicated fuel level increased by the prescribed amount (29.88 per gallon). Secondly, I'd watch the fuel 1 and 2 readings as the car is taking on fuel, to see if they fill evenly. This could also give us more insight as to how fuel enters / exits the tank.

Unless my car has a problem too, and I just haven't run it dry enough to experience it!!

BUT my gas gauge has never fluctuated or moved erratically.

George

 

A couple of readings (2004 STR):

range...........11....370 (set to show miles)
raw fuel 1.....98....231
raw fuel 2.....30....235
filter fuel 1....55....250
filter fuel 2.....0....253
fuel percent..25....254
fuel driver.....42....296

I forgot I let it go as low as 11

 

Is the 370 mile range with a full fill up? Reason I ask is your fuel percent number. Apparently all these ranges are SUPPOSED to have values between 0 and 254. I'm wondering if that's the data passed to the gas gauge or not. Or if that is a calculated number that the cluster comes up with.

George

 

Yep, after filling "full", i.e. filling until the fuel cuts off due to detecting fumes (I usually let it cut off twice) - but that can be before actually full, as the figures suggest. I don't struggle to keep filling as I would not want the risks of overfilling, don't need anything like that range (usually), and can't be bothered to take more time.

I just KNEW I shouldn't have posted about ETM lol

John

 

Yea, and I haven't even started messing with it yet.....Bwaaa Haa Haaa...

C'mon, it is fun though...

 

I had a BMW that in the summer loved to vapor lock the gas pump. Putting gas in the thing at some points became an ordeal. Pump would constantly click off. And I live in Jersey, which does NOT allow you to pump your own gas by law. So you

As far as the ETM. First, thanks for posting that PDF.

From that PDF, The fuel percent number drives the gas gauge.

What I'm trying to figure out is what's the difference between "raw fuel" and "filtered fuel".

It's obvious from all our cars, that side 2 levels drop faster, and that that is a normal condition.

Guess we're taking stabs in the dark here, but I think we have come up with a decent approximation of fuel reporting. I think the OP should fill his car. And write down the numbers directly before and after, and the amount of fuel he took on. We might be able to get a better insight into what is going on with his car.

George

 

Jeff, yeah, it is. How do you think I had those readings already? LOL

Reckon we should start a new thread about the CONFIG values? I reckon they'll include things like whether to sound the horn on double-locking, and maybe the wheel size (though that may just be a separate value).

 

I agree with that... the issue is unless one of us can come up with a Jaguar IDS computer, It's just going to be a reference point.

 

I'll fill it this afternoon and let you know what I see...

 

OK. I just filled her up. It took 11.61 Gallons. The fuel gauge was dead-on 1/2 tank and the dash read "103 mile to empty". When full, the needle was almost at full, and the rage read "292 miles to empty".

In test mode, it read the following before and after I filled-up:

Test.............Before After
range...........103...292
raw fuel 1.....99.....125
raw fuel 2.....30.....218
filter fuel 1....199...232
filter fuel 2.....0......0
fuel percent..114....245
fuel driver.....633...1351

Clearly, it had less than half a tank left when I put 11.61 gallons in it...

 

Something isn't Kosher here.

fuel percent = 114 - 114/254 = Right about a 1/2 tank = 44%

fuel percent = 245 - 245/254 = Almost full as described. = 96.4%

So the gauge is correctly showing the data it describes.

In all our cases the Raw fuel 2 number has been lower as has the Filtered Fuel 2 number, BUT this is indicative of consuming side 2 first. In your case there is NO filtered fuel in either case. This makes me think one of your fuel pumps may be gone, or reporting incorrectly.

With 99 and 30 as your raw fuel numbers. Per my calculations.. You had a total of 129 of raw fuel. 129 / 29.88 = 4.31 gallons. Add to that the 11.61 you took on, and you get 15.92 gallons of fuel. If Its reporting 17 gallons my guesstimate numbers are pretty close. What was your average MPG? You said 103 distance to empty right? Divide that by your average MPG and i bet it's close to 4.31. Which means the "raw fuel numbers" are right. But somehow the fuel percent is getting messed up.

Now, I guesstimated 29.88 "raw fuel" per gallon. 11.61 (gallons you took on) x 29.88 = 346.90 this is what your raw fuel number should have increased by. Yours Increased by 214. Yet your gas gauge was on the money. Something isn't reporting correctly here.

Either one of your fuel pumps isn't flowing right or senders is off on reporting, yet it seems like it may be alternating between over and underestimating the amount of fuel in the car.

How much do you drive? How long would it take you to get to say 2/3 of an indicated tank? Could you fill up again and give me pre and post numbers?

George

 

My guess would be a fuel sender (sensor) that's failing or has a bad connection or the like. But the car's basically working so unless you DIY is it worth the money you might spend getting someone to look at it?

 

Just back from the Dealer. They believe it's the fuel sending unit. They said it's a dual-part sender so they will order and replace both. They will install them next week when they receive them. I guess we'll find out next week if it needs something else...

Lucky for me they will be covered under warranty!!!

 

#$%#%,

My computer settings at work won't let me download the .pdf file. I'll have to wait until tonight to get it and figure out what they all mean. This might be the ultimate toy.

Mike

 

I was able to play around with the ETM and found that the Battery value of some value. When I tried the oil pressure value I got the following:

36 - Oil pressure OIL X Oil pressure. -L. -O.
-L=Good oil pressure
(open). -O=Low oil

pressure (ground).

WTF? L=good and O=Low oil pressure? Only the British would come up with that. Was hoping that it would read out oil pressure in PSI so I could use it as an oil pressure gauge.

 

Don't think it was the Brits as the cluster is a variant of Ford's HEC which I think is from the USA lol

I think the car only has a threshold sensor (oil good/bad), though I don't understand the symbol on the circuit diagram (apparently omitted from the "symbols" part of the electrical guide). The device is shown as wired to the GEM. Oh great, AutoEnginuity appears not to read it.

 

The S Type does have a humped or separated fuel tank. But the two fuel pumps have different functions on non-super charged cars. One is a jet pump that only transfers fuel from one tank to the other. The main fuel pump provides fuel to the engine. If you run out of fuel somewhere around the 1/2 way point then the jet pump has failed. I am not sure how balanced the jet pump keeps the two tanks? I thought it would be pretty close because of the weight balance?

Now the "R" cars have two fuel pumps that both supply fuel to the engine. No transfer pump.
.
.
.

 

Er... we've moved on to oil pressure and IAC the fuel pump / sensor issue was sorted out I understand (warranty claim).

 

I wanna have fun! What am I doing wrong here? Starting her up with trip button held down, says "engineering test mode" on the right instrament panel screen, then when I keep tapping the button on the stalk it just goes through my normal readings i.e. average speed, range, average mpg etc.!

 

You have an 05 so do you have the chrome-trimmed circular dials? If so, it's a newer ICM, which has different connectors on the rear, so there's every chance some other things changed too.

However, as it displays the ETM message it obviously has the mode. Try just releasing the stalk button once the message appears and waiting a few seconds. If the message stays then it's in the mode. If it then vanishes if you press the stalk button, my guess would be that you step throught the values using a different button. So.... re-enter ETM and instead of the stalk button try another. Er, there are quite a few LOL Like, the trip A/B, the km/ml etc. (I'm guessing a bit here.) Just keep messing

You found the TSB (JTB00014) about ETM? So you know to look for the dash lights all coming on, needles doing a full sweep, etc.